Twelve animals entered in this study with the aim of documenting that superior mesenteric artery small occlusions lasting for one hour have adverse effects on the myocardium. Three hours after cross clamp removal CO decreased to 1.07 +/- 0.11 from 1.99-0.09 a preoperative value (p < 0.01) and PCWP increased to 17 +/- 3 from 8 +/- 3 a preoperative value. MOE reduced to 40-5% 3 hours after cross clamp removal. MLE was -0.21 +/- 0.11 three hours after clamp removal. Changes in MOE and MLE were commented as a defect in myocardial aerobic metabolism. As a result of this study it was concluded that toxic mediators are released from the intestine being reperfused after temporary occlusions of the SMA impair myocardial metabolism, resulting in decreased hemodynamic functions.